Why do I get a ripple?

[Mustela]

Greeting everyone,

I am a new sewer and am having a consistent issue that I can't seem to solve.  When I am edgestitching long, relatively narrow (~1/2-1" wide) pieces of folded-over fabric (like for straps on a tote bag), a little ripple of fabric soon appears in front of the presser foot.  I think- though I am by no means certain- that the layers are shifting a bit, and causing a misalignment somehow (?), as oftentimes the edges of the fabric won't remain lined-up either.  Any thoughts as to what may be causing this -likely my self-taught technique- and how to remedy it would be GREATLY appreciated!

Thank You,
M

[kbenco]

Be assured, this is not just a new sewer problem.
There are a few reasons why this can happen. 1. When your 1/2 inch wide piece of fabric is folded, and you are edgestitching, the fabric you are sewing is most likely not touching the whole of the feed dog as it is just too skinny. This means that the fabric is being pulled along forwards, but also sideways towards the side of feed dog it is still touching, as that feed dog has resistance (fabric) and the other doesn't. You can help prevent this by butting up another piece of fabric to your edge, so that both feed dogs have some fabric to move.
2. If I am \ wrong about what I think you are describing, and both your feed dogs are covered, the ripple is more likely due to the bottom layer shifting at a faster rate than the top layer, as it is further away vertically from the feed dogs. This is most likely with slippery fabrics, heavy fabrics, and multiple layers. The easiest fix for this is a walking foot, but another fix is to firmly hold the fabric before and in front of where is being sewn, under gentle tension. You want the needle and feed dogs to have no strain on them, so you hold the fabric with equal tension in both directions, and let the machine feed along at its own rate. This takes practice, and if you hold the fabric under too much tension, the seam may ripple as the tension is removed.
I hope this helps.
Karen

[LauraS.]

You might also want to try some Steam-A-Seam (or A Lite).  Lay it out w/i the fold and press.  Shouldn't move. 

[BeeBee]

Basting - yes, the dreaded hand sewing kind - can also help.   

[Mustela]

Karen, LauraS, and BeeBee-

Thanks so much for these super-helpful replies!  It's great to have a varied "arsenal" through which to attack this problem.  I will try them all with renewed confidence!

Thanks again,
Mustela